Cobb recommend the HPFP with any 2 mods and a flash, so with BT I wouldnt even bother trying without it. They know a thing or two!
In the scheme of things $400 is a small price to pay for an insurance policy.
With my 3's mod list (AP, TMIC, SRI, TIP, DP) my fuel pressure was dropping pretty dangerously causing hesitation.
Here is the matrix;
http://www.ozmpsclub.com/forum/ecu-m...tml#post208213
MY16 WRX STi Crystal White Pearl
-= Rally Armour Flaps - 2XS Muffler Delete =-
FG FPV F6 MKII Vixen - SOLD
-= Bluepower SRI - ID1000 Injectors - Venom Cat - XCAL3 - ProcessWest Stg2 Intercooler - 359 RWKW=-
CX9 Grand Touring Stormy Blue
-= The rolling armchair =-
6 MPS Velocity Red - SOLD
-=Cat Back Exhaust - Pirelli PZero=-
3 MPS Aurora Blue - SOLD
-=PG SRI - PG Inlet - ETS TMIC - GFB Hybrid BOV - Best Mufflers DP - Eibach Pro - AccessPort STG2 - Autotech HPFP - ITV22 - Michelin PSS=-